Everything You Always Wanted to Know...

Everything You Always Wanted to Know About
Progressive (No-line) Multi-Focal Lenses (PAL’s) but Were Afraid to Ask
A progressive lens is not designed to have clear vision throughout the entire lens. In learning to wear a progressive lens you must remember that like an hourglass the corridor is narrower in the middle than the top and bottom. To use the middle portion you need to use your nose like a pointer and turn your head slightly to look directly at your object to get the full advantage of the intermediate area. If you glance to either side you will run into the blended area and your vision will blur slightly. To adjust the power between the distance and the near you must move you head slowly up or down which changes the power according to how far away the object or reading material is from you. Generally your near distance is measured at about 16 to 18 inches or elbow distance. The intermediate distance is between you elbow and about 6 inches beyond your finger tips. The far vision is anything beyond the ends of your finger tips. When wearing a progressive for the first time you must tilt your chin toward your chest and look over the intermediate blend to see the floor since it is beyond your fingertips. Sometimes, people who try progressive prescription lenses for the first time have a difficult time learning to look through the appropriate portion of the lens at the right time. Often a simple fitting adjustment to your prescription eyewear by your local optical professional can make all the difference.
In order to use a progressive lens, you must learn to move your head to see things; you cannot just move your eyes because you will be looking through a blurry part of the lens. This is called adapting to the lens. Most people can adapt within a month, but some people never adapt. It is common to experience dizziness and headaches during the time that you are adapting. Getting accustomed to progressive prescription glasses can be difficult, and you must have proper instruction by an eyecare professional.
Because of the relatively narrow vertical band of prescriptively accurate optics characteristic of progressive lenses, wearers may have some difficulty becoming used to the co-ordination of horizontal head movement necessary to retain focus when reading across a computer screen or a paper page. This is particularly true when the reading add power is strong (+2.00 or above). The experience has been described as "moving your head back and forth as if you are watching a tennis match". This can be mitigated by using high quality lenses, and by having your glasses made and fitted by a competent optician who is experienced in fitting progressive lenses. It is also beneficial to avoid the shallow eyeglass frames (i.e. the frames with very small vertical dimension) and choose a frame that is somewhat larger instead.
People who will work with the progressive lenses and learn to use them usually end up liking them.